<?php

/*
 * This file is part of SwiftMailer.
 * (c) 2004-2009 Chris Corbyn
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

/**
 * Analyzes UTF-8 characters.
 *
 * @author Chris Corbyn
 * @author Xavier De Cock <xdecock@gmail.com>
 */
class Swift_CharacterReader_Utf8Reader implements Swift_CharacterReader
{
    /** Pre-computed for optimization */
    private static $length_map = array(
        // N=0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,
        1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x0N
        1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x1N
        1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x2N
        1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x3N
        1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x4N
        1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x5N
        1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x6N
        1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x7N
        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 0x8N
        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 0x9N
        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 0xAN
        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 0xBN
        2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, // 0xCN
        2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, // 0xDN
        3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3, // 0xEN
        4,4,4,4,4,4,4,4,5,5,5,5,6,6,0,0,  // 0xFN
    );

    private static $s_length_map = array(
        "\x00" => 1, "\x01" => 1, "\x02" => 1, "\x03" => 1, "\x04" => 1, "\x05" => 1, "\x06" => 1, "\x07" => 1,
        "\x08" => 1, "\x09" => 1, "\x0a" => 1, "\x0b" => 1, "\x0c" => 1, "\x0d" => 1, "\x0e" => 1, "\x0f" => 1,
        "\x10" => 1, "\x11" => 1, "\x12" => 1, "\x13" => 1, "\x14" => 1, "\x15" => 1, "\x16" => 1, "\x17" => 1,
        "\x18" => 1, "\x19" => 1, "\x1a" => 1, "\x1b" => 1, "\x1c" => 1, "\x1d" => 1, "\x1e" => 1, "\x1f" => 1,
        "\x20" => 1, "\x21" => 1, "\x22" => 1, "\x23" => 1, "\x24" => 1, "\x25" => 1, "\x26" => 1, "\x27" => 1,
        "\x28" => 1, "\x29" => 1, "\x2a" => 1, "\x2b" => 1, "\x2c" => 1, "\x2d" => 1, "\x2e" => 1, "\x2f" => 1,
        "\x30" => 1, "\x31" => 1, "\x32" => 1, "\x33" => 1, "\x34" => 1, "\x35" => 1, "\x36" => 1, "\x37" => 1,
        "\x38" => 1, "\x39" => 1, "\x3a" => 1, "\x3b" => 1, "\x3c" => 1, "\x3d" => 1, "\x3e" => 1, "\x3f" => 1,
        "\x40" => 1, "\x41" => 1, "\x42" => 1, "\x43" => 1, "\x44" => 1, "\x45" => 1, "\x46" => 1, "\x47" => 1,
        "\x48" => 1, "\x49" => 1, "\x4a" => 1, "\x4b" => 1, "\x4c" => 1, "\x4d" => 1, "\x4e" => 1, "\x4f" => 1,
        "\x50" => 1, "\x51" => 1, "\x52" => 1, "\x53" => 1, "\x54" => 1, "\x55" => 1, "\x56" => 1, "\x57" => 1,
        "\x58" => 1, "\x59" => 1, "\x5a" => 1, "\x5b" => 1, "\x5c" => 1, "\x5d" => 1, "\x5e" => 1, "\x5f" => 1,
        "\x60" => 1, "\x61" => 1, "\x62" => 1, "\x63" => 1, "\x64" => 1, "\x65" => 1, "\x66" => 1, "\x67" => 1,
        "\x68" => 1, "\x69" => 1, "\x6a" => 1, "\x6b" => 1, "\x6c" => 1, "\x6d" => 1, "\x6e" => 1, "\x6f" => 1,
        "\x70" => 1, "\x71" => 1, "\x72" => 1, "\x73" => 1, "\x74" => 1, "\x75" => 1, "\x76" => 1, "\x77" => 1,
        "\x78" => 1, "\x79" => 1, "\x7a" => 1, "\x7b" => 1, "\x7c" => 1, "\x7d" => 1, "\x7e" => 1, "\x7f" => 1,
        "\x80" => 0, "\x81" => 0, "\x82" => 0, "\x83" => 0, "\x84" => 0, "\x85" => 0, "\x86" => 0, "\x87" => 0,
        "\x88" => 0, "\x89" => 0, "\x8a" => 0, "\x8b" => 0, "\x8c" => 0, "\x8d" => 0, "\x8e" => 0, "\x8f" => 0,
        "\x90" => 0, "\x91" => 0, "\x92" => 0, "\x93" => 0, "\x94" => 0, "\x95" => 0, "\x96" => 0, "\x97" => 0,
        "\x98" => 0, "\x99" => 0, "\x9a" => 0, "\x9b" => 0, "\x9c" => 0, "\x9d" => 0, "\x9e" => 0, "\x9f" => 0,
        "\xa0" => 0, "\xa1" => 0, "\xa2" => 0, "\xa3" => 0, "\xa4" => 0, "\xa5" => 0, "\xa6" => 0, "\xa7" => 0,
        "\xa8" => 0, "\xa9" => 0, "\xaa" => 0, "\xab" => 0, "\xac" => 0, "\xad" => 0, "\xae" => 0, "\xaf" => 0,
        "\xb0" => 0, "\xb1" => 0, "\xb2" => 0, "\xb3" => 0, "\xb4" => 0, "\xb5" => 0, "\xb6" => 0, "\xb7" => 0,
        "\xb8" => 0, "\xb9" => 0, "\xba" => 0, "\xbb" => 0, "\xbc" => 0, "\xbd" => 0, "\xbe" => 0, "\xbf" => 0,
        "\xc0" => 2, "\xc1" => 2, "\xc2" => 2, "\xc3" => 2, "\xc4" => 2, "\xc5" => 2, "\xc6" => 2, "\xc7" => 2,
        "\xc8" => 2, "\xc9" => 2, "\xca" => 2, "\xcb" => 2, "\xcc" => 2, "\xcd" => 2, "\xce" => 2, "\xcf" => 2,
        "\xd0" => 2, "\xd1" => 2, "\xd2" => 2, "\xd3" => 2, "\xd4" => 2, "\xd5" => 2, "\xd6" => 2, "\xd7" => 2,
        "\xd8" => 2, "\xd9" => 2, "\xda" => 2, "\xdb" => 2, "\xdc" => 2, "\xdd" => 2, "\xde" => 2, "\xdf" => 2,
        "\xe0" => 3, "\xe1" => 3, "\xe2" => 3, "\xe3" => 3, "\xe4" => 3, "\xe5" => 3, "\xe6" => 3, "\xe7" => 3,
        "\xe8" => 3, "\xe9" => 3, "\xea" => 3, "\xeb" => 3, "\xec" => 3, "\xed" => 3, "\xee" => 3, "\xef" => 3,
        "\xf0" => 4, "\xf1" => 4, "\xf2" => 4, "\xf3" => 4, "\xf4" => 4, "\xf5" => 4, "\xf6" => 4, "\xf7" => 4,
        "\xf8" => 5, "\xf9" => 5, "\xfa" => 5, "\xfb" => 5, "\xfc" => 6, "\xfd" => 6, "\xfe" => 0, "\xff" => 0,
     );

    /**
     * Returns the complete character map.
     *
     * @param string $string
     * @param int    $startOffset
     * @param array  $currentMap
     * @param mixed  $ignoredChars
     *
     * @return int
     */
    public function getCharPositions($string, $startOffset, &$currentMap, &$ignoredChars)
    {
        if (!isset($currentMap['i']) || !isset($currentMap['p'])) {
            $currentMap['p'] = $currentMap['i'] = array();
        }

        $strlen = strlen($string);
        $charPos = count($currentMap['p']);
        $foundChars = 0;
        $invalid = false;
        for ($i = 0; $i < $strlen; ++$i) {
            $char = $string[$i];
            $size = self::$s_length_map[$char];
            if ($size == 0) {
                /* char is invalid, we must wait for a resync */
                $invalid = true;
                continue;
            } else {
                if ($invalid == true) {
                    /* We mark the chars as invalid and start a new char */
                    $currentMap['p'][$charPos + $foundChars] = $startOffset + $i;
                    $currentMap['i'][$charPos + $foundChars] = true;
                    ++$foundChars;
                    $invalid = false;
                }
                if (($i + $size) > $strlen) {
                    $ignoredChars = substr($string, $i);
                    break;
                }
                for ($j = 1; $j < $size; ++$j) {
                    $char = $string[$i + $j];
                    if ($char > "\x7F" && $char < "\xC0") {
                        // Valid - continue parsing
                    } else {
                        /* char is invalid, we must wait for a resync */
                        $invalid = true;
                        continue 2;
                    }
                }
                /* Ok we got a complete char here */
                $currentMap['p'][$charPos + $foundChars] = $startOffset + $i + $size;
                $i += $j - 1;
                ++$foundChars;
            }
        }

        return $foundChars;
    }

    /**
     * Returns mapType.
     *
     * @return int mapType
     */
    public function getMapType()
    {
        return self::MAP_TYPE_POSITIONS;
    }

    /**
     * Returns an integer which specifies how many more bytes to read.
     *
     * A positive integer indicates the number of more bytes to fetch before invoking
     * this method again.
     * A value of zero means this is already a valid character.
     * A value of -1 means this cannot possibly be a valid character.
     *
     * @param string $bytes
     * @param int    $size
     *
     * @return int
     */
    public function validateByteSequence($bytes, $size)
    {
        if ($size < 1) {
            return -1;
        }
        $needed = self::$length_map[$bytes[0]] - $size;

        return $needed > -1 ? $needed : -1;
    }

    /**
     * Returns the number of bytes which should be read to start each character.
     *
     * @return int
     */
    public function getInitialByteSize()
    {
        return 1;
    }
}
